It's a prototype. Paper reticule stuck to a CD and CD transparent cover, with an old cdrom plastic spigot, to allow rotation of the disks.
The main function is to convert local date/time to the northern hemisphere reticule. The numbers in brackets (and pencil on the outer edge) are local date and time.
One thing that is immediately apparent and very handy is alternative alignments, which makes it easier to set up - circled
Yes there are electronic versions - iphone, but this was fun to make. I've compared it to Stellarium and there is no discernable error in the placement of Sig Oct on the reticule.
Thanks to Dennis for his original tak pas converter program.
